The present invention relates generally to the field of computer networks, and more particularly to allocating network resources in a virtualized computer network.
In system virtualization, multiple virtual systems are created within a single physical system. The physical system can be a stand-alone computer, or alternatively, a computing system utilizing clustered computers and components. Virtual systems are independent operating environments that use virtual resources made up of logical divisions of physical resources such as processors, memory and input/output (I/O) adapters. This system virtualization is implemented through some managing functionality, typically hypervisor technology. Hypervisors, also called virtual machine managers (VMMs), use a thin layer of code in software or firmware to achieve fine-grained, dynamic resource sharing. Because hypervisors provide the greatest level of flexibility in how virtual resources are defined and managed, they are the primary technology for system virtualization.
It is a common requirement today for virtualized environments to be able to enforce strict partitioning between different classes of workload, while still sharing hardware between workloads of the same class. Separation may be required for several reasons. One reason may be to enable high availability, such that two clustered workloads do not share a single point-of-failure. Another reason is for performance guarantees, such that the resource demands of one class of resources do not affect another class. A third reason is the concern for confidentiality. For example, two competing organizations may wish to utilize a single provider of virtualized environments, with the requirement that hardware is not shared. Typically, the unit of segregation is that of a single host system, i.e. a single instance of a hypervisor.
Multipathing allows a virtual machine to continue to communicate with external systems when a given physical adapter, or physical port, is not operating, either due to equipment failure or due to maintenance operations such as a firmware update. Multipathing is used extensively in mission-critical workloads to ensure continuity of service during hardware failure. It is typical to ensure that no single point of failure exists between a virtual machine and the external systems to which it connects.